Containers for filling with a beverage, such as cans for carbonated soft drinks and beer, are now produced with very thin gauge materials, such as aluminum. Due to the cost of the cans or the like, the use of less material in forming the can is desired, but has led to problems when filling the can with a beverage using high speed automated beverage filling machines and equipment. Such containers have also been configured with a necked down region at the top of the cans to define a reduced diameter opening, thereby reducing size of the cap needed for closure thereof.
In a high speed automated beverage filling machine, the filling of a can is performed by positioning the can into a filling position relative to a filling valve. For high speed operation, the filling stations are rotated at high speed and cans are sequentially introduced to the filling machine from a conveyor system for filling, and then removed for further processing steps. Upon positioning of the can in a filling station and sealing in association with a filling valve, the can is first charged with carbon dioxide to counter pressure the can, and then an amount of a beverage is introduced therein, such as from an elevated beverage bowl. After filling, the filled can is snifted to remove any remaining gases under pressure. Thereafter, the can may be removed from the filling valve and subsequent capping or other processes are performed.
During filling, the cans are generally lifted into a filling position via a platform, relative to a filling valve, and the necked down top is engaged by a sealing gasket associated with the filling valve. To prevent leakage, the sealing gasket engages the top of the can with some force for proper sealing. If the position of the can relative to the sealing gasket and filling valve is not accurate when lifted into position by a lifting platform, this can result in damage to the can. With the thinner side walls and necked down region at the top, cans may be damaged during the filling process such as by buckling, crimping or crinkling, particularly at higher fill speeds. Damage to cans during filling causes significant problems such as lower production, leakage or costs of discarding materials or product, limiting production and/or making production costs higher. Prior practice was to install a set of lock levers in a filler, then shim the structures, such as the bowl height, utilizing shims under the bowl stanchions located in a circular pattern around the bowl. Shims would be added or subtracted until the valves in front of the stanchions measured out to the desired height + or −0.005 inches for example. These attempts may still result in the valves between the stanchion being out of the + or − range as described. Any differential from the desired position is detrimental to the filling operation as a slight deviation in this range will cause a short fill or an over filled can, whereas a larger deviation will cause the can side wall to buckle or the can will not fill at all.
Alternatively, the proper positioning of the support platform on which a can rests relative to a filling station is adjusted to properly position a can thereon relative to the fill valve, and avoid damage to cans or problems in filling. The function of the lock levers on a can filling machine is to provide a device which is used to fix or lock the height of the platform the empty can sits on in relation to the filling valve located directly above a respective filling station. This is important for correct operation of the filling process at all stations around the multiple station filler.
Prior practice was to measure each fill station as to the position or height of the lift platform in association with a filler. If any fill stations did not have the desired height of the platform, installers have attempted to shim the beverage bowl height utilizing shims under the bowl stanchions located at intervals around the bowl. Shims would be added or subtracted until the valves in front of the stanchions measured out to the desired height within a predetermined tolerance. Although this may result in correction of problems at or directly adjacent a bowl stanchion, fill valves situated between the stanchions could still be out of the tolerance range. This differential is detrimental to the filling operation as a slight deviation in this range will cause a short fill or an over filled can, cause the can side wall to buckle or otherwise deform, or result in the can not filling at all. Any such occurrences or problems are very costly and wasteful to an efficient and effective filling process. Due to such parameters, or others, such as the tolerances of the piston support ring associated with the platform lift cylinder, beverage bowl dimensional fluctuations or other structures or dimensional characteristics associated with the automated filling machine, the fill positions of each of the platforms can vary, requiring a different required positioning of an associated lock lever. Another attempt by installers to correct these problems was by adjusting the position of lock lever support surface, by shimming or shaving material from the lock lever. Such an approach is labor intensive and no simple solutions have been developed. In a further attempt, there has been provided an adjustable eccentric pivot post that the lock lever rotates around. This approach still requires every station to be measured and set to the correct height every time the lock lever is installed or replaced, or where the adjustment eccentric moves from its set position. It is common for the eccentric adjustment device to rotate over a period of time, resulting in making that fill station out of tolerance. It would be desirable to avoid the need for performing such adjustments on the fly during installation or replacement, and provide an easier method of adjusting the position of a lift platform of a fill station in association with a lock lever in an automated beverage filling machine.
One other detriment to the standard lock lever is that as the lock lever is being rotated to its proper position, there is a point approximately five degrees prior to the operative location of the lock lever where the platform is raised 0.020 to 0.030 inches higher than the desired height or height range. This can result in problems of jolting a portion of the beverage in the container such that it escapes the container before filling is completed, or possible damage to the can. It would be desirable to provide a lock lever which avoids this unwanted raising of the platform beyond the desired height.
Also, in the use of lock levers in association with automated beverage filling machines, the levers periodically must be replaced. Presently, there is no solution for simple replacement of a lock lever when needed. Depending on the initial set up parameters associated with each lock lever in a machine, if adjustments were made during initial set up, any replacement lock lever must also be adjusted, requiring the maintenance personnel to independently determine if an adjustment is necessary, and if so, what adjustment is necessary to position the lock lever and therefore the lift platform at the proper position. It would therefore be desirable to provide a system and method for simple and effective maintenance and replacement of lock levers associated with a particular filling machine.